Non-loaded Manual Blade Fold Assembly for Rotorcraft
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Solution Overview
Problem
Conventional blade folding systems for rotary-wing aircraft are cumbersome and susceptible to drag, limiting their efficiency in flight and requiring significant structural space, which hinders rapid deployment and stowage in limited environments.
Innovation Solution
A rotor blade fold assembly featuring a linkage system with a plurality of coupled links that supports the blade only when folded, allowing for reduced structural envelope and efficient deployment, transport, and operation by rotating between aligned and rotated positions, with pins carrying loads during flight and the linkage supporting the blade in the folded state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional blade folding systems are used to reduce structural envelope, then the aircraft can be stored in limited space, but the systems become cumbersome and susceptible to drag
Solution Approach 1:
The rotor blade is divided into two separate sections: a first section that remains stationary and a second section that folds independently. This segmentation allows the blade to reduce its radial envelope for storage while maintaining aerodynamic integrity during flight, eliminating the drag issues of conventional folding systems.
Solution Approach 2:
The folding mechanism is extracted from the traditional hub-based system and repositioned to operate between two blade sections. The linkage system is designed to be compact and only occupy space when the blade is in the folded position, removing the cumbersome drag-generating components from the flight configuration.
2Productivity
If conventional blade folding systems are used to facilitate rapid deployment, then transport capability is improved, but the systems require significant structural space
Solution Approach 1:
The blade folding system employs dynamic linkages that can rapidly transition between folded and unfolded positions. The linkage design allows for quick deployment during operations while collapsing into a compact configuration during transport, optimizing both deployment speed and space efficiency.
Solution Approach 2:
When the blade is in the folded position, the linkage system nests within the radial space of the rotor hub assembly. The second blade section folds over the first section, with the linkage mechanism compactly arranged within the available space, minimizing the structural envelope during transport.
3Volume of moving object
If conventional blade folding systems are used to reduce structural envelope, then stowage capability is improved, but the systems are cumbersome
Solution Approach 1:
The folding linkage system is merged with the blade structure itself rather than being a separate hub-mounted mechanism. The linkage connects the two blade sections and integrates with the blade's structural components, simplifying the overall system while achieving the desired envelope reduction for stowage.
Data Source
AI summary
A rotor blade configured to fold about a blade fold axis includes a first section and a second section. The first section is configured to mount to a rotor hub and includes a first connector having at least one first opening. The second section includes a second connector having at least one second opening. The second section is rotatably coupled to the first section and is configured to rotate about the blade fold axis between an aligned position and a rotated position. A linkage is operably coupled to the first section and the second section. The linkage includes a plurality of links loosely connected such that the linkage is configured to support the second section of the rotor blade only when the second section is in the rotated position.